package 开始的算法算法入门8月.广度优先搜索深度优先搜索;
// https://leetcode-cn.com/problems/merge-two-binary-trees/
public class 合并二叉树6170819 {

     public class TreeNode {
         int val;
         TreeNode left;
         TreeNode right;
         TreeNode() {}
         TreeNode(int val) { this.val = val; }
         TreeNode(int val, TreeNode left, TreeNode right) {
             this.val = val;
             this.left = left;
             this.right = right;
         }
     }

    class Solution {
        public TreeNode mergeTrees(TreeNode t1, TreeNode t2) {
            if (t1 == null) {
                return t2;
            }
            if (t2 == null) {
                return t1;
            }
            TreeNode merged = new TreeNode(t1.val + t2.val);
            merged.left = mergeTrees(t1.left, t2.left);
            merged.right = mergeTrees(t1.right, t2.right);
            return merged;
        }
    }

}
